Spekker Katrin, Czesla Markus, Ince Vanessa, Heseler Kathrin, Schmidt Silvia K, Schares Gereon, Däubener Walter
Institute of Medical Microbiology and Hospital Hygiene, Heinrich Heine University, Düsseldorf, Germany.
Infect Immun. 2009 Oct;77(10):4496-501. doi: 10.1128/IAI.00310-09. Epub 2009 Jul 20.
Neospora caninum is an apicomplexan parasite closely related to Toxoplasma gondii. In nature this parasite is found especially in dogs and cattle, but it may also infect other livestock. The growth of N. caninum, which is an obligate intracellular parasite, is controlled mainly by the cell-mediated immune response. During infection the cytokine gamma interferon (IFN-gamma) plays a prominent role in regulating the growth of N. caninum in natural and experimental disease. The present study showed that induction of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) is responsible for the inhibition of parasite growth that is mediated by IFN-gamma-activated bovine fibroblasts and endothelial cells. This antiparasite effect could be abrogated by addition of tryptophan, as well as by the IDO-specific inhibitor 1-L-methyltryptophan. In conclusion, our data show that human and bovine cells use the same effector mechanism to control the growth of N. caninum.
犬新孢子虫是一种与刚地弓形虫密切相关的顶复门寄生虫。在自然界中，这种寄生虫尤其在犬和牛体内发现，但它也可能感染其他家畜。犬新孢子虫是一种专性细胞内寄生虫，其生长主要受细胞介导的免疫反应控制。在感染过程中，细胞因子γ干扰素（IFN-γ）在调节犬新孢子虫在自然和实验性疾病中的生长方面发挥着重要作用。本研究表明，色氨酸降解酶吲哚胺2,3-双加氧酶（IDO）的诱导是由IFN-γ激活的牛成纤维细胞和内皮细胞介导的寄生虫生长抑制的原因。添加色氨酸以及IDO特异性抑制剂1-L-甲基色氨酸可消除这种抗寄生虫作用。总之，我们的数据表明，人和牛细胞使用相同的效应机制来控制犬新孢子虫的生长。
